<!DOCTYPE html>
<html lang="zh-Hans">
  <head>
    <meta charset="UTF-8" />
    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
    <title>弹跳球效果</title>
    <link rel="stylesheet" href="style.css" />
  </head>

  <body>
    <div class="box">
      <div class="ball"></div>
      <div class="shadow"></div>
    </div>
  </body>
</html>
